The invention relates to a device for forming a dental prosthesis.
The dental prosthesis can have only one single artificial tooth or only one artificial dental crown or two or more artificial teeth or dental crowns.
Devices for forming a dental prosthesis known under the ITI mark on the market have a support and a cap which can be fastened thereon and serves to form an artificial dental crown. The support has a base or primary part and a secondary part which can be detachably connected thereto. The base has a first end, which sits in a hole of a jawbone during the use of the device, a second end projecting from the jawbone, an axial hole which opens into this end and has a section with an internal thread. The base has a conical annular surface which surrounds the mouth of the hole and which serves as a bearing surface for the cap. The secondary part serves as a holder for holding the cap and has an inner part which is screwed into the hole of the base, an octagonal head situated outside the base, and an axial threaded hole opening into the end face of the head. The cap consists of a gold alloy and has a conical countersurface which rests on the conical bearing surface of the base and a hole which is coaxial with the axis of the support and the countersurface of the cap. The cap is fastened on the secondary part with a screw which penetrates the hole and is screwed into the threaded bore of the secondary part. During use of the device, additional materials are also applied to the originally approximately frustoconical cap so that, together with the materials applied, an artificial dental crown having the desired shape is formed.
In these known devices, the hole of the cap opens in the apical end of the cap facing away from the jawbone. The head of the screw accordingly lies, in an artificial molar, in or below the masticating surface of the crown which is in part formed by the cap. In an artificial incisor or canine, the screw head is situated, for example, below or close next to the cutting part of the dental crown. The hole of the cap and the screw therefore hinder optimum formation of the dental crown. This is the case in particular in incisors. In addition, the screw head is aesthetically disturbing.
The devices known under the mark ITI are used not only for replacing individual teeth but also for fastening and/or forming bridges replacing a number of teeth and in this case have two or more supports, on which a cap is fastened in each case. A connection element forming at least one artificial tooth is arranged between these and connected by cast or soldered connections to the caps which consist of a gold alloy. In order that the caps can be mounted on the octagonal heads of the supports, the axes of the two supports must be reasonably accurately parallel with one another. Accordingly, the holes drilled in the jawbone for receiving the bases must be reasonably accurately parallel with one another so that great accuracy is necessary when drilling these holes.
The aim of the invention is to produce a device having at least one support and at least one cap, which makes it possible to eliminate disadvantages of the known devices, and in particular to avoid the hole of the cap having to be coaxial with the axis of the support and the screw serving for fastening the cap having to have a head lying at the apical end of the cap.